The present invention relates to the field of nutritional supplements and, more particularly, to a composition comprising an extract of kava-kava root and a method for the extraction of kava-kava root compounds.
Supercritical CO2 has been used for about 20 years to extract non-polar compounds such as lipids, including fatty acids and sterols from solid plant material. Typical products of supercritical fluid extraction (SFE) include decaffeinated coffee and tea, essential oils from hops used in brewing, and extraction of aromas and flavors from spices and herbs.
The technology of supercritical CO2 extraction advantageously employs the increased dissolving power of CO2 increases at high pressures. At pressures less than the critical pressure of CO2, solubilities are essentially nil, but as the pressure is increased to several thousand pounds per square inch, the CO2 has the dissolving power of a liquid, but the flow characteristics of a gas. Thus, CO2 can easily flow through a pressurized extraction vessel containing powdered kava-kava root and quickly dissolve the non-polar oily constituents. The product-laden CO2 then flows to a separation vessel where pressure is lowered and the CO2 passes off as a gas, leaving the extract behind as recovered product. The CO2 is recycled, compressed, and the process repeated.
Herbal products such as kava-kava root extract have long been used as home remedies and dietary supplements in many parts of the world. Kava-kava root has previously been extracted through a standard method using ethanol as the solvent. This prior art process results in an extract providing an insufficient yield of kavalactones, which comprise the desired components of kava-kava root. In addition, ethanol extracts of the root have the further undesirable property of including a certain amount of the solvent in the final product. The typical extraction process of the kava-kava root for kavalactones produces a yield of about 40-50% kavalactones, and a yield of at most 0.3% of flavokawain. The average industry percentage of kavalactone of a kava-kava extract is less than 70% and contains harmful solvent residue.
The present invention relates to herbal extracts and processes for herbal extracts. More specifically, it relates to herbal extracts of whole kava-kava root to obtain a liquid, semi-solid extracts, and/or paste extracts whereby these extracts are obtained through a supercritical carbon dioxide fluid extraction process.
With the foregoing in mind, the present invention advantageously provides a method for extracting kava-kava root, a composition comprising the extract, and a method of nutritional supplementation employing the extract.
Supercritical fluid extraction of kava-kava (Piper methysticum) at a preferred pressure and temperature yields a paste extract having a much higher percentage of kavalactone and flavokawain than is obtainable with previous processes. When the extraction process is conducted according to the present invention, at a pressure above 500 bar and a temperature range of 450xc2x0 C. to 65xc2x0 C., the extract is separated from the CO2 in the form of a paste having a kavalactone percent by weight of greater than 70% and a flavokawain of approximately 30% by weight. The kava-kava extract contains kavalactones at percentages surprisingly higher than industry standard.
Other than the present invention, kava extraction is generally conducted by producing a dry extract using conventional liquid solvents in the extraction process, and particularly ethanol. Supercritical CO2 has been previously employed for extracting kava-kava root, but at the pressures employed, substantially lower than 500 bar, recovery of kavalactones is not significantly higher than with ethanol extraction. The present invention employs supercritical fluid extraction at higher pressures to achieve its unexpectedly higher kavalactone concentrations. The kavalactone percentage by weight in the kava extract obtained in this inventive process is greater than 70% with no harmful solvent residue.
In the present invention, whole, dried kava root is ground to a fineness of from about minus 40 to about plus 60 mesh. The supercritical carbon dioxide extraction process is conducted at pressures of at least 500 bar, and at temperatures from 45xc2x0 C. to 65xc2x0 C. The high pressure and relatively low temperature conditions increase yields of the desired kava compounds while preserving favorable qualities of the extract produced, for example, resulting in an extract having a relatively low oxidation state.